Analog Devices LTC7820 | Demoboard DC2543

Description

Demonstration circuit 2543A is a high efficiency, highdensity, open loop charge pump (inductorless) DC/DCconverter. This demo board is a voltage divider whichachieves a 2:1 step-down ratio from an input voltage from36V to 60V. The output voltage is a fixed ratio of half of theinput voltage (VIN/2) and can supply a 10A load current.This demo board has the option to deliver a 20A maximumload with the addition of 15 chip capacitors. See Figures 8and 10 for the details.The DC2543A provides a very high efficiency solution of98.7% when converting 48VIN to 24VOUT at 10A as shownin Figure 3. When configured for a 20A output, an efficiencyof up to 98.4% is achievable for a 48VIN to 24VOUTat 20A as shown in Figure 8.The demo board features the LTC®7820, a fixed ratio highvoltage high power switched capacitor/charge pumpcontroller in a 4mm × 5mm QFN package. Please seeLTC7820 data sheet for more detailed information.The DC2543A needs to be powered on with no load currentor a very small load current (less than 50mA) with thedefault setup. Large load current can be applied after VOis established. The board offers a disconnect FET optionwhich is controlled by the LTC7820 FAULT pin to disconnectthe load during startup as shown in the schematic.Please refer to “Voltage Divider Prebalance Before Switching”section in the LTC7820 data sheet for more detailsregarding the startup of the voltage divider. The board alsofeatures some protection functions such as overcurrentand thermal shutdown to make it a reliable solution.

More information

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